JP3339073B2 - Fully closed reference position signal correction device for control valve of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a correction device for a fully closed reference position signal of a control valve of an internal combustion engine, and more particularly to a correction device for correcting a fully closed reference position signal extracted from a device for detecting an opening degree of an exhaust gas recirculation valve. .

[0002]

2. Description of the Related Art Conventionally, a part of exhaust gas of an internal combustion engine is recirculated into an intake air-fuel mixture through an exhaust gas recirculation valve, and heat generated by combustion in an engine cylinder is deprived by inert gas in the exhaust gas to achieve maximum combustion. by lowering the temperature, nitrogen oxides (NO _X) to reduce the exhaust gas recirculation in an exhaust gas (EGR:
Exhaust gas recirculation devices are known. In this EGR device, when the EGR is performed, the output may decrease or the combustion may become unstable. Therefore, the exhaust gas recirculation amount (EGR amount) is appropriately controlled by controlling the opening degree of the exhaust gas recirculation valve according to the operation state. are doing.

However, when a change occurs in the fully closed reference position due to thermal expansion, aging, etc. of the exhaust gas recirculation valve, the output opening detection value of the exhaust gas recirculation valve opening detection device and the actual opening degree of the exhaust gas recirculation valve are reduced. Error occurs, and it becomes impossible to perform appropriate EGR amount feedback control.

Therefore, conventionally, when the state in which the opening command value of the exhaust gas recirculation valve indicates that the exhaust gas recirculation valve is fully closed has continued for a predetermined time, the output opening detection value of the opening detection device after the elapse of the predetermined time has been used as a fully closed reference. A fully-closed reference position signal correction device in which the position is updated is known (JP-A-57-188753).

[0005]

By the way, the frequency of use of the exhaust gas recirculation valve is most often used in the fully closed position. For example, the frequency of use of the exhaust gas recirculation valve during the LA # 4 mode travel specified in the United States is 55.3% as shown in FIG. At the time of EGR operation, the use frequency of an extremely low lift amount of 0 to 0.5 mm is 21.4% as shown by II, which exceeds 70%. Note that III indicates that the exhaust gas recirculation valve is fully opened and stopped.

[0006] Therefore, since the exhaust gas recirculation valve is often fully closed, the resistance of the opening detection device near the fully closed position is greatly worn due to engine vibration, and the extremely low lift Since the amount is frequently used, overshooting and undershooting are repeated, so that the resistance of the resistor of the opening detection device is also large near the fully closed position.

Further, the exhaust gas recirculation valve has a deposit (deposits of carbon fine particles) adhered to the sheet due to long-term use, and the manner of adhesion is not uniform. An error occurs in the fully closed position due to biting of the above-mentioned deposits or fine dust contained in the exhaust gas.

Therefore, the opening detection value of the exhaust gas recirculation valve opening detection device at the time of the fully closed command is poor in reliability due to the wear of the resistor near the fully closed position, and the detected value of the fully closed position due to foreign matter being caught by the foreign matter. Due to the occurrence of errors, the above-described conventional fully-closed reference position signal correction device cannot obtain an accurate fully-closed detection value, and therefore cannot ensure the accuracy of the EGR flow rate, and adversely affects exhaust emission, drivability, and fuel efficiency. Is generated.

The present invention has been made in view of the above points,
An object of the present invention is to provide a fully-closed reference position signal correction device for a control valve of an internal combustion engine that solves the above-mentioned problem by updating a fully-closed reference position signal with a control valve stroke amount and a fully-open position signal at the time of a new vehicle. I do.

[0010]

In order to achieve the above object, the present invention, as shown in the principle block diagram of FIG. 1, comprises an opening detecting device 11 for detecting an opening of a control valve 10 and first to third openings. Calculation means 12, 13 and 14. The first calculating means 12 controls the control valve 1 when the traveling distance is less than a predetermined value.
The stroke amount which is the difference between the fully closed position and the fully opened position of 0 is calculated. When the travel distance is equal to or greater than the predetermined value, the second calculating means 13 determines whether the control valve 10 is fully opened and the fully-opened position signal extracted from the opening degree detecting device 11 and the first calculating means 12 The difference from the stroke amount is calculated. Third
Calculating means 14 compares the value of the difference calculated by the second calculating means 13 between the time of the previous full-open instruction and the time of the present full-open instruction, and, based on the comparison result, the fully closed state corresponding to the difference value. Update and output the reference position signal.

[0011]

The stroke amount calculated by the first calculating means 12 is a value for a new vehicle whose traveling distance is less than the predetermined value. At this time, since the control valve 10 is similar to a new one, an accurate stroke amount is calculated. can do. Control valve 1
Since the frequency of use at the fully open position of 0 is much less than that at the time of fully closed, the wear of the resistor when the control valve 10 of the opening degree detecting device 10 is fully opened is much less than at the time of fully closed. Even if the value exceeds the predetermined value, the deterioration of the fully open position signal is small.

Therefore, in the present invention, the fully-closed reference position signal is updated from the fully-opened position signal and the stroke amount each time the control valve 10 is instructed to be fully opened by the second calculating means 13 and 14, thereby obtaining the fully-closed reference value. It is possible to obtain a more accurate fully closed reference position signal than updating the position signal with the detected value of the fully closed position.

[0013]

FIG. 2 is a schematic system configuration diagram of an internal combustion engine to which the present invention is applied. In the figure, an exhaust gas recirculation valve 20 corresponds to the control valve 10, and a diaphragm 21 and a spring 22
And a needle valve (valve element) 23. Diaphragm 2
1, a spring 22 urges a spring force downward in the figure, one end of a needle valve 23 is fixed at the center thereof, and one end of a rod 33 of the lift sensor 30 is further fixed. . When the exhaust gas recirculation valve 20 is fully closed, the needle valve 23 is connected to the opening 4 of the EGR gas passage 40 as shown in the figure.
3 is closed.

The lift sensor 30 is connected to the opening detecting device 11.
And comprises a resistor 31, a slider 32 and a rod 33. A predetermined DC voltage is applied between both ends of the resistor 31. Further, the slider 32 is fixed to the rod 33, and moves integrally with the movement of the needle valve 23 via the rod 33 and the diaphragm 21 to move the resistor 3
1 slide on. As a result, a voltage having a resistance division ratio corresponding to the position on the resistor 31, that is, an opening detection voltage having a level corresponding to the position of the needle valve 23 is extracted from the slider 32.

The EGR gas passage 40 has a gas passage 41 communicating with an exhaust manifold (not shown) as an exhaust passage of the internal combustion engine, and a gas passage 42 communicating with an intake manifold (not shown) as an intake passage of the internal combustion engine. The gas passages 41 and 42 are configured to communicate with each other through the opening 43. Further, the opening area of the opening 43 is controlled by the position of the needle valve 23 (that is, the opening area is set to an opening area corresponding to the opening degree of the exhaust gas recirculation valve 20).

The three-way solenoid valve 50 includes a solenoid 51, valves 52 and 53, and has a first port P ₁ communicating with the atmosphere, a second port P ₂ communicating with the exhaust gas recirculation valve 20, and an intake pipe negative pressure. Third port P _{3 that} communicates
have. The solenoid 51 is connected to an electronic control unit 6 described later.
It is energized during the high level of the drive pulse from 0, and is de-energized during the low level.

As a result, the solenoid 51 turns off the valve 52 and turns on the valve 53 when energized to reduce the negative pressure of the intake pipe input to the port P ₃ through the valve 53 and the port P ₂ in the exhaust gas recirculation valve 20. Then, the diaphragm 21 is sucked upward in the drawing against the spring force of the spring 22, and the needle valve 23 is moved upward accordingly to open the opening 43.

When the solenoid 51 is not energized, the valve 52 is turned on and the valve 53 is turned off, and the exhaust recirculation valve 20 is communicated with the atmosphere through the port P ₁ , the valve 52 and the port P _2. 2
In the figure, the needle valve 23 is moved downward by the spring force of 2, and the needle valve 23 is moved downward to close the opening 43. Therefore, the opening area of the opening 43, that is, the opening degree of the exhaust gas recirculation valve 20, changes according to the duty ratio of the drive pulse supplied to the solenoid 51.

The electronic control unit 60 receives from the lift sensor 30 an opening detection voltage corresponding to the position of the needle valve 23 of the exhaust gas recirculation valve 20, and receives the first to third calculating means 12 to
14 comprises a central processing unit (CPU) 61 for realizing the software processing operation, a memory 62 for storing programs and data, a drive circuit 63 for sending drive pulses to the solenoid 51, and the like.

Next, a fully closed reference position signal correction routine executed by the electronic control unit 60 to realize the first to third calculation means 12 to 14 will be described. FIGS. 3 and 4 are flowcharts (parts 1 and 2) of the first embodiment of the fully closed reference position signal correction routine which is an essential part of the present invention. When this routine is started, for example, in a part of the main routine, it is first determined whether or not the traveling distance is less than a predetermined value (step 101).

This predetermined value is set to the maximum value of the traveling distance at which the vehicle equipped with the internal combustion engine is considered to be a new vehicle. The valve 20 is in a new condition, there is no deposit, and the lift sensor 30 has thermal expansion, aging,
It is determined that the resistors 31 have not deteriorated, and the process proceeds to the next step 102. If the travel distance is equal to or more than the predetermined value, it is determined that the vehicle is not a new vehicle, and the process proceeds to step 109 in FIG.

In step 102, it is determined whether or not the operating condition is a fully closed condition in which EGR is not performed (for example, at the time of deceleration, an idle state, etc.). If the operating condition is fully closed, a drive pulse is sent from the drive circuit 63 to the solenoid 51. The solenoid 51 is kept in the non-energized state without being output, and the opening 43 is closed by the needle valve 23. Then, proceed to Step 103,
From the fully closed condition establishment determining step 102 determines whether or not a predetermined time t ₂ has elapsed. This is because the needle valve 23 moves to the fully closed position when the exhaust gas recirculation valve 20 is at a certain opening even if the fully closed condition is satisfied in step 102 and the solenoid 51 is de-energized by the electronic control unit 60. This is because a physical delay occurs before the operation is completed, and it is necessary to consider this physical delay at the time of determination.

Since the predetermined time t ₂ is set slightly longer than the time required for the needle valve 23 to complete the movement from the fully open position to the fully closed position, the predetermined time t ₂ elapses in step 103. when it is determined by the a, the needle valve 23 advances to step 104 and determined to be complete moved to the fully closed position, and stores it in the memory 62 takes in the output voltage C ₀ of the lift sensor 30 at that time.

When the conditions of steps 102 and 103 are not satisfied, or when the processing of step 104 is completed, it is determined whether or not an operating condition for fully opening the exhaust gas recirculation valve 20 (for example, at a high speed and a high load) has been reached. If it is determined (step 105) that the full-open condition is not satisfied, this routine is temporarily terminated. If the full-open condition is satisfied, a predetermined time t after the full-open condition is satisfied
It is determined whether _{1 has} elapsed (step 106).

The predetermined time t ₁ is the time from when the electronic control unit 60 outputs the energizing signal to the solenoid 51 (after the full-open instruction is issued) until the needle valve 23 actually moves to the full-open position. It is set to a value slightly larger than the maximum value. Accordingly, when it is determined in step 106 that t> t _1, it is determined that the needle valve 23 is at the fully open position, and at that time, the electronic control unit 60
Fetches the output voltage B ₀ supplied to the
7) Store in the memory 62.

Here, the voltage output from the slider 32 of the lift sensor 30 and the needle valve 23 (the exhaust gas recirculation valve 20)
Is in a proportional relationship as shown in FIG. Therefore, by subtracting the voltage C ₀ out full-closing of the new car from the fully open detection voltage B ₀ of new car in the next step 108, the voltage A obtained showing the stroke amount a of the needle valve 23. Also,
This voltage A indicates the original correct stroke amount when the exhaust gas recirculation valve 20 is in a new state. Step 105
, 106, the routine is terminated once.

When the processing in step 108 is completed, or when it is determined in step 101 that the traveling distance is equal to or more than the predetermined value, the process proceeds to step 109 in FIG. 4 under operating conditions (fully open conditions) in which the exhaust gas recirculation valve 20 is fully opened. It is determined whether there is. When not fully open condition to end this routine, when the full open condition is determined whether or not a predetermined time t ₁ has elapsed from the time of establishment step 109 (step 110), this routine when not the predetermined time t ₁ has elapsed once completed, the exhaust gas recirculation valve 20 after a predetermined time t ₁ has elapsed it is determined that (the needle valve 23) is physically fully open position, takes in the output voltage B of the lift sensor 30 at that time (step 111) It is stored in the memory 62.

Subsequently, the voltage B captured in step 111
By subtracting the voltage A indicating the stroke amount calculated in step 108 and stored in the memory 62 from the above, the detected voltage Ci at the fully closed position of the exhaust gas recirculation valve 20 at this time is calculated (step 112). In other words, even if the traveling distance becomes a predetermined value or more and the exhaust gas recirculation valve 20 changes over time, the frequency of use of the fully open condition is low, so that the wear of the resistor 31 at the fully open position is much larger than the wear at the fully closed position. Even if the deposit adheres to the opening 43, there is no effect at the time of full opening even if the deposit adheres to the opening 43. Therefore, in the step 111, there is little variation, and the fully open position detection voltage B according to the environment (resistor temperature, etc.) at that time is obtained. can get.

Accordingly, in step 112, the voltage A indicating the original stroke amount A is subtracted from the fully open position detection voltage B, thereby obtaining the accurate fully closed position detection voltage C at that time.
i is obtained. When the calculation of the fully-closed position detection voltage Ci in step 112 is completed, subsequently, in step 113, when this routine was started last time, the fully-closed position detection voltage Ci _-1 similarly calculated in step 112 and this time Is determined to be within the range from a predetermined lower limit α to an upper limit β. This is to prevent erroneous detection when the fully closed position detection voltage Ci (or C _i-1 ) slightly fluctuates due to noise or the like.

Therefore, in step 113, α <C _i−1 −Ci
When it is determined that <β, it is determined that there is no substantial difference in the fully closed position detection voltage Ci (or Ci _-1 ) between the previous time and the current time, and the routine is terminated. On the other hand, if it is determined in step 113 that the above inequality expression is not satisfied, the magnitudes of the fully closed position detection voltages Ci and Ci _-1 are compared (step 114).

When it is determined that Ci _-1 > Ci, a predetermined value .DELTA.C is added to Ci _-1 to obtain the current fully-closed position detection voltage Ci (step 115), and it is determined that Ci _- 1≥Ci. When C
_A predetermined value ΔC is subtracted from _i−1 to obtain a current fully closed position detection voltage Ci (step 116). That is, the fully closed position detection voltage Ci is calculated based on the magnitude comparison result of step 114 by C
i is updated by adding or subtracting a predetermined value ΔC to or from the previous value C _i−1 in step 115 or 116 so as to approach i.
Is used as the fully closed reference position signal. When the update process is completed, the current fully closed position detection voltage Ci is substituted for Ci _-1 (step 117) in order to enable the next process, and the routine ends.

When the travel distance is equal to or greater than the predetermined value, the processing of steps 109 to 117 is periodically performed, and every time the exhaust gas recirculation valve 20 is instructed to be fully opened, the detection voltage Ci serving as the fully closed reference position signal is changed. It is updated according to the result of the magnitude comparison between Ci _-1 and Ci.

As described above, according to the present embodiment, the first calculating means 12 is realized by steps 101 to 108 of FIG. 3, and the second calculating means 13 is realized by steps 109 to 112 of FIG. , Steps 113 to 116 can implement the third calculating means 14. Thus, in the present embodiment, the fully closed position detection voltage C, which is easily affected by the mounting tolerance of the lift sensor 30, the tolerance and wear of the resistor 31 over time, and furthermore, the deposit, is changed to the fully open position detection voltage B with little variation factor. Since the calculation is made based on the difference from the stroke amount detection voltage A at the time, a substantially accurate fully closed position detection voltage C with little variation can be obtained.

Also, since the mounting tolerance of the lift sensor 30 can be sufficiently absorbed, the yield can be improved and the mass production cost can be reduced. Further, according to the present embodiment, it is not necessary to use an expensive resistor 31 of the lift sensor 30, so that the cost of the entire apparatus can be reduced.

Next, the second part of the fully closed reference position signal correction routine will be described.
An example will be described. FIG. 6 shows a flowchart of the main part of the second embodiment of the fully closed reference position signal correction routine.
In the figure, the same parts as those of the processing steps of FIG. In this embodiment, the steps in FIG.
3 is the same as the routine of FIG. 3. After the detection voltage A of the stroke amount is calculated in step 108 of FIG. 3, or when the traveling distance is equal to or more than a predetermined value, the process proceeds to step 121 of FIG. lift amount indicated by the detection voltage is determined whether it is larger than the predetermined value L _1.

[0036] The predetermined value L ₁ is set to low, and Ru certain example fully open and fully closed intermediate position detection voltage more than the fully opened position detection voltage. After forcibly fully open the exhaust gas recirculation valve 20 when it is determined that the lift amount> L ₁ in step 121 (step 122), the aforementioned steps
The Ci update processing of 110 to 117 is executed. Then, after the processing in step 117, the solenoid 5 is operated so that the output detection voltage of the original lift sensor 30 in step 121 is obtained.
The duty ratio of 1 is controlled (step 123), and this routine ends.

In the first embodiment, when the traveling distance is equal to or more than a predetermined value, the fully closed position detection voltage (fully closed reference position signal) Ci unless the operating condition for fully opening the exhaust gas recirculation valve 20 is satisfied.
In this embodiment, when the opening degree of the exhaust gas recirculation valve 20 is close to the full opening to some extent, the updating processing of the Ci is performed by forcibly opening the exhaust gas recirculating valve 20. Learning opportunities can be increased, and more reliable fully closed reference position signal correction can be performed.

In this embodiment, the exhaust gas recirculation valve 20 is forcibly set.
Set value L of operation area to be fully opened ₁To a value close to full throttle
By limiting, without impairing drivability
Update processing can be performed.

[0039]

As described above, according to the present invention, when the traveling distance is equal to or greater than the predetermined value, the fully closed reference position is obtained from the latest fully-opened position detection voltage and a signal indicating the original stroke amount without deterioration in a new vehicle. Since the signal is updated, it is possible to obtain a highly reliable fully closed reference position signal corrected in accordance with environmental conditions, rather than updating the fully closed reference position signal based on the fully closed detection voltage. It has features.

[Brief description of the drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a schematic system configuration diagram of an internal combustion engine to which the present invention is applied.

FIG. 3 is a flowchart (part 1) of a first embodiment of a fully closed reference position signal correction routine which is a main part of the present invention.

FIG. 4 is a flowchart (part 2) of a first embodiment of a fully closed reference position signal correction routine which is a main part of the present invention.

FIG. 5 is a diagram showing a relationship between an opening degree of an exhaust gas recirculation valve and a lift sensor output voltage.

FIG. 6 is a second flowchart of the fully closed reference position signal correction routine according to the present invention;
It is a flowchart of the principal part of an Example.

FIG. 7 is an explanatory diagram of an example of a lift distribution of an exhaust gas recirculation valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Control valve 11 Opening detection device 12 1st calculating means 13 2nd calculating means 14 3rd calculating means 20 Exhaust recirculation valve 21 Diaphragm 22 Spring 23 Needle valve (valve element) 30 Lift sensor 31 Resistor 32 Sliding Element 40 EGR gas passage 43 Opening 50 Solenoid valve 60 Electronic control unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-134057 (JP, A) JP-A-55-93950 (JP, A) JP-A-61-108858 (JP, A) JP-A-60-1985 105911 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02M 25/07 550 F02D 45/00 301 F02D 45/00 368 G01B 21/22

Claims (1)

(57) [Claims] An opening detection device for detecting an opening of a control valve of an internal combustion engine, and a stroke amount that is a difference between a fully closed position and a fully opened position of the control valve when a traveling distance is less than a predetermined value. When the travel distance is equal to or greater than the predetermined value, each time the control valve is instructed to fully open, a fully open position signal extracted from the opening degree detection device and the first calculation means A second calculating means for calculating a difference from the stroke amount, and comparing the value of the difference calculated by the second calculating means between the previous full opening instruction and the current full opening instruction. A third calculating means for updating and outputting a fully closed reference position signal corresponding to the value of the difference in response to the difference value.